Sulfur is a yellow solid that is a nonmetal. It is brittle (easily broken) and crystalline. It burns easily, releasing toxic fumes of sulfur dioxide. It has a very faint odor. If it is melted and cooled very quickly, it makes a rubbery form of sulfur that is called "plastic sulfur". It gradually turns back into the yellow brittle form. It does not dissolve in water. The smell normally known as "sulfur" comes from hydrogen sulfide and similar chemicals. These sulfides are produced when things decay without air.

Sulfur powder made by reacting sulfur dioxide and hydrogen sulfide from coal

Sulfur can be found in the earth near volcanoes. Many minerals contain sulfur ions. Coal contains sulfur ions which are released when it burns. Hydrogen sulfide and sulfur dioxide are some sulfur compounds that are released when coal burns. They are reacted to make sulfur. Sulfur in the ground in melted, then forced up through pipes by compressed (squeezed) air.

Sulfur is commonly used in gunpowder, medicine, and matches. Matches release sulfur dioxide when they burn, giving them their smell. Sulfur is an essential component to living cells. Many proteins contain sulfur. It is also used as a pesticide on organic farms.

The ancient name for sulfur is brimstone. Sulfur was used in fumigation (making fumes) and medicine in ancient Greece. In 1777, Antoine Lavosier convinced the scientific community that sulfur was an element.